Which stars are considered the main sequence stars?
(earth science)​

Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive. Stars start their lives as clouds of dust and gas.

In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness.

How can you tell if a star is a main sequence star?

For a star to be located on the Main Sequence in the H-R diagram:

It must be in Hydrostatic Equilibrium (Pressure balances Gravity)

It must be in Thermal Equilibrium (Energy Generation balances Luminosity)

It must generate energy by "burning" Hydrogen into Helium in its core.

* A red dwarf is the smallest and coolest kind of star on the main sequence. Red dwarfs are by far the most common type of star in the Milky Way, at least in the neighborhood of the Sun, but because of their low luminosity, individual red dwarfs cannot be easily observed.

the answer would be 3

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.